Distal hereditary motor neuronopathy of the Jerash type (HMNJ) is characterized by distal muscle weakness and atrophy. SIGMAR1 mutations have recently been associated with other motor neuron diseases. We have identified a novel SIGMAR1 c.500A>T missense mutation that is associated with HMNJ in 30 patients. We proved that this mutation reduces the expression and alters the subcellular localization of the SIGMAR1 protein, while cells expressing this mutant exhibit increased cell death. Our data strongly supports that the SIGMAR1 c.500A>T mutation is responsible for the development of HMNJ, and we propose that SIGMAR1 be included in diagnostic panels for motor neuropathies. (By Prof. Kyproula Christodoulou, https://jmg.bmj.com/content/early/2019/09/10/jmedgenet-2019-106108 )

HMNJ SIGMAR1 mutation disturbs the localisation and expression of wild-type SIGMAR1